CN112689973B

CN112689973B - Method and apparatus for integrated access and backhaul node selection

Info

Publication number: CN112689973B
Application number: CN201880097479.1A
Authority: CN
Inventors: 吴联海; P·巴苏·马利克; J·勒尔; 刘红梅; 汪海明; 韩晶
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2018-09-21
Filing date: 2018-09-21
Publication date: 2023-09-22
Anticipated expiration: 2038-09-21
Also published as: EP3854032A1; CN112689973A; US20220053365A1; US11792681B2; WO2020056749A1; EP3854032A4

Abstract

The present invention relates to a method and apparatus. According to some embodiments of the invention, a method comprises: receiving information of a triggering condition for configuring the integrated access and backhaul node to report load information of at least one integrated access and backhaul node; and reporting the load information of the at least one integrated access and backhaul node if the trigger condition is met, wherein the load information includes a load status indicator of the integrated access and backhaul node.

Description

Method and apparatus for integrated access and backhaul node selection

Technical Field

The present invention relates generally to wireless communication technology, and more particularly to wireless communication technology for handling integrated access and backhaul node selection in a wireless communication system.

Background

In the third generation partnership project (3 GPP), deployment of relay nodes (hereinafter referred to as "RNs") in wireless communication systems is being facilitated. One of the main purposes of deploying RNs is to enhance the coverage area of a base station (hereinafter referred to as "BS") by improving the throughput of mobile devices (also referred to as User Equipments (UEs)) that are positioned in a coverage hole or far from the base station (resulting in low signal quality).

In a wireless communication system employing RNs, a BS that can provide a connection with at least one RN is referred to as a donor BS. The RN is connected to the donor BS through a backhaul link. The RN may skip one or more RNs before reaching the donor BS, or may be directly connected to the donor BS. A procedure for selecting candidate nodes of an RN in a wireless communication system is desired.

Disclosure of Invention

Embodiments of the present invention provide a method comprising: receiving information of a triggering condition for configuring the integrated access and backhaul node to report load information of at least one integrated access and backhaul node; and reporting the load information of the at least one integrated access and backhaul node if the trigger condition is met, wherein the load information includes a load status indicator of the integrated access and backhaul node.

Another embodiment of the present invention provides a method comprising: transmitting information for configuring the integrated access and backhaul node to report a trigger condition for the load information of at least one integrated access and backhaul node; and receiving the load information of the at least one integrated access and backhaul node, wherein the load information includes a load status indicator of the integrated access and backhaul node.

Embodiments of the present invention also provide a non-transitory computer readable medium. According to an embodiment of the invention, the non-transitory computer readable medium has stored therein computer executable instructions to cause a processor to implement a method according to an embodiment of the invention.

The embodiment of the invention also provides equipment. In an embodiment of the invention, an apparatus comprises: a non-transitory computer readable medium having stored therein computer executable instructions; receiving circuitry; transmitting circuitry; and a processor. The processor is coupled to the non-transitory computer-readable medium, the receive circuitry, and the transmit circuitry. Wherein the computer-executable instructions are programmed to cause the processor to implement a method according to an embodiment of the invention.

Drawings

In order to describe the manner in which the advantages and features of the invention can be obtained, a description of the invention is presented by way of reference to particular embodiments of the invention, which are illustrated in the accompanying drawings. These drawings depict only example embodiments of the invention and are not therefore to be considered to limit its scope.

Fig. 1 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

Fig. 2 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

fig. 3 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

fig. 4 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

fig. 5 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

fig. 6 illustrates an exemplary wireless communication system in accordance with an embodiment of the present invention;

FIG. 7 illustrates an exemplary process for selecting a node according to an embodiment of the invention;

FIG. 8 illustrates an exemplary process for selecting a node according to an embodiment of the invention; and

Fig. 9 illustrates an example block diagram of an apparatus according to an embodiment of the invention.

Detailed Description

The detailed description of the drawings is intended as a description of the preferred embodiments of the invention and is not intended to represent the only forms in which the invention may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the invention.

Fig. 1 illustrates a wireless communication system 100 according to an embodiment of the invention.

As shown in fig. 1, for simplicity, assume that wireless communication system 100 includes: a plurality of nodes including BS 10 and RN 20; and a plurality of UEs including UEs 30A and 30B. It should be noted that the wireless communication system 100 may also include multiple BSs and/or multiple RNs.

The BS 10 operates under the control of a Mobility Management Entity (MME) 40 and is connected to a Core Network (CN) 50. The core network also includes a Home Subscriber Server (HSS) (not shown) in communication with the MME. The BS 10 may be based on, for example, long Term Evolution (LTE), LTE-advanced (LTE-a), new Radio (NR) standards, or other suitable standards. For example, BS 10 may be an eNB or a gNB and may define one or more cells, such as cell 11. The UEs 30A and/or 30B may be computing devices, wearable devices, or mobile devices, among others. Those skilled in the art will appreciate that as 3GPP (third generation partnership project) and communication technologies evolve, the terminology set forth in the specification may change, which should not affect the principles of the invention.

BS 10 provides radio protocol layer-1 (physical layer) to layer-3 (radio resource control (RRC) layer) connections with UE 30B and RN 20 via Access Link (AL) and Backhaul Link (BL), respectively. In some embodiments, RN 20 provides radio protocol layer-1 to layer-3 connections with UE 30A over RN access link (AL 1). In other embodiments, RN 20 provides radio protocol layer-1 to layer-2 connections with UE 30A through AL 1. Since the RN 20 is connected to the BS 10 through a Backhaul Link (BL), the BS 10 and the RN 20 correspond to the above-mentioned donor BS and RN, respectively. Although fig. 1 shows that the donor BS 10 and the RN 20 are respectively connected to a single UE, the donor BS 10 and the RN 20 can provide connection with a plurality of UEs.

The relay function enables an operator to improve and expand coverage of the BS by having the RN wirelessly connected to the BS. An evolved universal terrestrial radio access network (E-UTRAN) supports relaying by having the RN wirelessly connect to an eNB serving the RN, referred to as donor eNB (DeNB), via a modified version of the evolved universal terrestrial radio access (E-UTRA) radio interface, i.e., a Backhaul Link (BL), also referred to as the Un interface. The radio interface providing a radio protocol connection between the RN and the UE is referred to as Uu interface. The relay function and purpose of the RN/DeNB entity in the network is transparent to the operation of the connected UE.

The 3GPP is envisioning an Integrated Access and Backhaul (IAB) architecture for 5G (NR) communication networks supporting multi-hop relay. That is, the IAB node may skip one or more IAB nodes before reaching the donor BS. A single jump should be considered as a special case of multiple jumps. Multi-hop backhaul is beneficial because it provides a larger range extension than single-hop backhaul. Higher frequency bands, such as frequency bands above 6GHz, have limited range radio signals and may benefit from this greater range expansion. The multi-hop loop further enables a return trip around obstacles such as buildings that clutter the urban environment of deployment.

The maximum number of hops in the intended deployment depends on a number of factors, such as frequency, cell density, propagation environment, and traffic load. These factors are expected to change over time. As the number of hops increases, scalability issues may arise. For example, performance may degrade and/or signaling load may increase to unacceptable levels.

Fig. 2 illustrates a wireless communication system 200 according to an embodiment of the invention. As shown in fig. 2, for simplicity, assume that wireless communication system 200 includes: a plurality of nodes including donor nodes, i.e., IAB donors; and a plurality of IAB nodes including IAB nodes 0 to 3; and a plurality of access nodes including UE 0 and UE 1. It should be noted that the wireless communication system 200 may also include a plurality of donor nodes.

In fig. 2, for simplicity, it is assumed that IAB node 0 and IAB node 3 are directly connected to the same donor node, i.e., IAB donor. Note that IAB node 0 and IAB node 3 may be connected to different donor nodes. IAB node 2 may reach the IAB donor by skipping IAB node 3. IAB node 3 is the parent IAB node of IAB node 2. In other words, the IAB node 2 is a child node of the IAB node 3. IAB node 1 may reach the IAB donor by skipping IAB node 2 and IAB node 3. IAB node 2 and IAB node 3 are upstream IAB nodes of IAB node 1, and IAB node 2 is a parent IAB node of IAB node 1. In other words, IAB node 1 is a child node of IAB node 2, and IAB nodes 1 and IAB node 2 are downstream IAB nodes of IAB node 3. UE 0 and UE 1 are directly connected to IAB node 0 and IAB node 1, respectively. Note that multiple UEs (not shown) may be directly connected to IAB nodes 0-3, respectively. In addition, a plurality of IAB nodes may be directly connected to IAB nodes 0 to 3.

Fig. 3 illustrates a wireless communication system 300 according to an embodiment of the invention.

As shown in fig. 3, the IAB node and UE may be connected to a Next Generation Core (NGC). Each IAB node may include a Distributed Unit (DU) and a Mobile Terminal (MT). An IAB node may be connected to an upstream IAB node or IAB donor via an MT and may be connected to a UE and a downstream IAB node via a DU. The IAB donor may include DUs to support UEs and MTs of downstream IAB nodes. The IAB donor may further include a Centralized Unit (CU) for all IAB nodes and its own DUs. The IAB node in fig. 3 may sometimes be referred to as a layer-2 (L2) IAB node. In some embodiments, the IAB nodes in fig. 2, e.g., IAB nodes 0 through 3, may be L2 IAB nodes.

Fig. 4 illustrates a wireless communication system 400 according to an embodiment of the invention.

As shown in fig. 4, the IAB node and UE may be connected to the NGC. Each IAB node may include a gNB and an MT. The IAB node may be connected to an upstream IAB node or IAB donor via an MT and may be connected to a UE and a downstream IAB node via a gNB. The IAB node may further include a User Plane Function (UPF) co-located with the gNB in the IAB node. The IAB node in fig. 4 may sometimes be referred to as a layer-3 (L3) IAB node. In some embodiments, the IAB nodes in fig. 2, e.g., IAB nodes 0 through 3, may be L3 IAB nodes.

Fig. 5 illustrates a wireless communication system 500 according to an embodiment of the invention. In fig. 5, multiple connectivity is implemented. For example, as shown in fig. 5, IAB node 3 may be connected to more than one IAB node, including IAB node 1 and IAB node 2. In other words, the IAB node 1 and the IAB node 2 share a sub-IAB node, i.e., IAB node 3. In this case, the IAB node 3 will have multiple paths to the donor node (i.e., IAB donor) via multiple parent IAB nodes (i.e., IAB node 1 and IAB node 2). For example, IAB node 3 may reach the IAB donor by skipping IAB node 0 and IAB node 1. Alternatively, the IAB node 3 may reach the IAB donor by skipping the IAB node 2. From the perspective of a node downstream of the IAB node 3 (e.g., the IAB node 4), the IAB node 4 also has multiple paths through the IAB node 3 to the IAB donor. Note that multiple connectivity may also be implemented on one or more other IAB nodes in a wireless communication system.

Fig. 6 illustrates a wireless communication system 600 according to an embodiment of the invention. In fig. 6, IAB node 4 may reach the donor node by skipping IAB node 2 and IAB node 3, i.e. the IAB donor, and IAB node 1 may reach the IAB donor by skipping IAB node 0.

In an IAB node-less wireless communication system, a Radio Link Failure (RLF) between a UE and a BS may be declared in response to at least one of: the RLF timer (e.g., T310) expires, a Random Access (RA) failure, or a Radio Link Control (RLC) re-transmission to a maximum number. In response to the RLF, the UE may perform a reestablishment procedure. The UE may enter idle mode in response to a failure in the reestablishment procedure.

In a wireless communication system employing an RN, in response to RLF on a Un interface between the RN and the DeNB, the RN may switch to UE mode without Un subframe restriction and perform a normal contention-based Random Access Channel (RACH) procedure. For example, referring to fig. 1, in response to RLF between the RN 20 and the donor BS 10, the RN 20 may switch to UE mode and perform a normal contention-based RACH procedure. In response to a successful reconstruction, the RN subframe configuration is reconfigured. In response to a failure in the reestablishment, the RN may enter idle mode and attempt to recover. Meanwhile, the RN may stop the Uu interface between the RN and the UE attached to the RN by, for example, stopping the Master Information Block (MIB) and/or system information block 1 (SIB 1) transmission.

In a wireless communication system supporting multi-hop relay, a wireless backhaul link may be broken, for example, for reasons such as blocking due to moving objects such as vehicles, plants (caused by seasonal changes), or new buildings (caused by infrastructure changes). Physically stationary IAB nodes may experience this problem. For example, referring to fig. 6, rlf may occur on the backhaul link between the IAB donor and the IAB node 2. In this example, IAB node 2 may be handed off from an IAB donor to another donor node (not shown). In another example, still referring to fig. 6, rlf may occur on a backhaul link between two IAB nodes, such as IAB node 3 and IAB node 2. In this example, the IAB node 3 may initialize a reestablishment procedure, select a target IAB node to reestablish the backhaul link, and access the target IAB node. For example, the IAB node 3 may be handed off from the IAB node 2 to a target IAB node, such as IAB node 1.

In addition, traffic variations can cause uneven load distribution on the wireless backhaul links, which can lead to congestion on the local links or nodes. For example, referring to fig. 6, when the traffic load on IAB node 2 is too heavy, the IAB donor may initiate a procedure to hand over a child node of IAB node 2 (e.g., IAB node 3) to a target IAB node (e.g., IAB node 1).

Accordingly, a procedure for selecting a target IAB node in a wireless communication system is desired. This process may be applied to handover and re-establishment processes as described above.

To select a target IAB node, load information for one or more candidate IAB nodes may be provided. In addition, measurement results and other ancillary information such as hop counts may also be helpful. Accordingly, a method for determining load information of an IAB node is also desired.

Embodiments of the present invention propose a technical solution for target node selection that may address at least the above technical problems in a new generation communication system, such as a 5G communication system. Further details regarding embodiments of the present invention will be described in the following text in conjunction with the drawings.

Fig. 7 illustrates an exemplary process 700 for selecting a target node according to an embodiment of the invention.

The iab node may receive information for configuring a trigger condition in step 702. If the trigger condition is met, the IAB node will be triggered to report load information of at least one IAB node. In some embodiments of the invention, the IAB node may be the L2 IAB node shown in fig. 3 or the L3 IAB node shown in fig. 4.

In some embodiments of the present invention, the trigger condition may be configured by the BS. For example, referring to fig. 6, the IAB node 3 may receive trigger information from an IAB donor via dedicated signaling.

In some embodiments of the invention, the IAB node may also report its own load information. For example, referring to fig. 6, the IAB node 3 may receive information for configuring the IAB node 3 to report trigger conditions for load information of at least one IAB node. At least one IAB node may comprise an IAB node 3.

In some embodiments of the present invention, the at least one IAB node may further comprise a candidate IAB node of the IAB node and an upstream IAB node of the candidate IAB node. For example, referring to fig. 6, the IAB node 3 may receive information for configuring the IAB node 3 to report trigger conditions for load information of at least one IAB node. IAB node 1 may be one of the candidate nodes for IAB node 3. The at least one IAB node may include IAB node 1 and its upstream IAB node, e.g., IAB node 0.

In some embodiments, the at least one IAB node may further include a serving IAB node of the IAB node and an upstream IAB node of the serving IAB node. For example, referring to fig. 6, the IAB node 3 may receive information for configuring the IAB node 3 to report trigger conditions for load information of at least one IAB node. At least one IAB node may include IAB node 2 and its upstream IAB node (if present).

In step 704, the IAB node reports load information of at least one IAB node if the trigger condition is met. In some embodiments, the IAB node may further report the measurement results and other assistance information such as hop count.

In some embodiments, the load information of the IAB node refers to the number of access nodes (e.g., X) of the IAB node. In one embodiment, the number of access nodes of an IAB node refers to the number of access nodes (e.g., X1) directly connected to the IAB node. In another embodiment, the number of access nodes of an IAB node refers to the number of access nodes directly connected to the IAB node plus the number of access nodes (e.g., X2) directly connected to the respective downstream IAB node of the IAB node. In some embodiments, the access node may be an access UE.

In other embodiments, the load information of the IAB node refers to the number X of access nodes of the IAB node plus the number of IAB nodes of the IAB node (e.g., Y). In one embodiment, the number of access nodes X of an IAB node refers to the number of access nodes X1 of an IAB node that are directly connected to the IAB node, and the number of IAB nodes Y of an IAB node is the number of sub-IAB nodes (e.g., Y1) that are directly connected to the IAB node. In another embodiment, the number of access nodes X of an IAB node refers to the number of access nodes directly connected to the IAB node plus the number of access nodes X2 of the corresponding downstream IAB node directly connected to the IAB node, and the number of IAB nodes Y of the IAB node refers to the number of downstream IAB nodes of the IAB node (e.g., Y2). In some embodiments, the access node may be an access UE.

In yet other embodiments, the load information of the IAB node comprises a load status indicator of the IAB node. In some embodiments, the load status indicator of the IAB node may indicate a load level of the plurality of load levels. In one embodiment, the load status indicator may indicate a low load, a medium load, or a high load of the IAB node.

In some embodiments, the IAB node may further receive at least one threshold for the load state. In one embodiment, at least one threshold may be configurable by the BS. For example, referring to fig. 6, the IAB node 3 may receive at least one threshold from an IAB donor via dedicated signaling. In other embodiments, the IAB node may receive a broadcast message including at least one threshold of load status. In one embodiment, the broadcast message is broadcast by a parent IAB node of the IAB node. For example, referring to fig. 6, the IAB node 3 may receive at least one threshold broadcast by its parent IAB node (e.g., IAB node 2).

In some embodiments, the at least one threshold includes a first threshold (e.g., H1) and a second threshold (e.g., H2). In these embodiments, the load status indicator of the IAB node indicates a low load of the IAB node in case the number X of access nodes of the IAB node is smaller than the first threshold H1. In case the number X of access nodes of the IAB node is equal to or greater than the first threshold H1 and smaller than the second threshold H2, the load status indicator of the IAB node indicates a medium load of the IAB node. In case the number X of access nodes of the IAB node is equal to or larger than the second threshold H2, the load status indicator of the IAB node indicates a high load of the IAB node.

In some embodiments, the number of access nodes X of the IAB node may be X1, as described above. In other embodiments, the number of access nodes X of an IAB node is calculated based on the number of access nodes directly connected to the IAB node and the number of access nodes directly connected to respective downstream IAB nodes of the IAB node. In one embodiment, the number of access nodes X of the IAB node may be X2.

In a preferred embodiment, the IAB node and at least one neighboring IAB node may share a sub-IAB node. For example, referring to fig. 5, IAB nodes 1 and 2 share a sub-IAB node 3. In this embodiment, the number X of access nodes of the IAB node may be calculated by:

-dividing equally the number of access nodes of the sub-IAB node between the IAB node and at least one neighboring IAB node; and

-adding the divided number of access nodes to the number of access nodes directly connected to the IAB node.

For example, referring to fig. 5, the number of access nodes for IAB node 1 may be calculated by equally dividing the number of access nodes for IAB node 3 between IAB nodes 1 and 2 and adding the divided number to the number of access nodes directly connected to IAB node 1. For example, when IAB node 1 is serving 100 UEs and its downstream IAB nodes (i.e., IAB nodes 3 and 4) are serving 50 UEs, i.e., the number of UEs directly connected to IAB node 1 is 100 and the number of UEs of IAB node 3 is 50, the number of access nodes of IAB node 1 may be calculated by: 100+50/2=125. The number of access nodes for IAB node 2 may be similarly calculated.

In another preferred embodiment, the number X of access nodes of the IAB node may be calculated by:

-adding the number of access nodes directly connected to the IAB node to the number of access nodes of the sub-IAB node of the IAB node.

In this embodiment, the number of access nodes of a sub-IAB node of an IAB node is calculated based on the load status indicator of the sub-IAB node. As mentioned above, the load status indicator of the IAB node may indicate the load level of the plurality of load levels. In one example, the load status indicator may indicate a low load, a medium load, or a high load of the IAB node. In this example, where the load status indicator of the child IAB node indicates a low load, the number of access nodes of the child IAB node is half the first threshold H1, i.e. H1/2. In case the load status indicator of the sub-IAB node indicates a medium load, the number of access nodes of the sub-IAB node is the average of the first threshold H1 and the second threshold H2, i.e., (h1+h2)/2. In case the load status indicator of the sub-IAB node indicates a high load, the number of access nodes of the sub-IAB node is half the second threshold H2, i.e. H2/2. In other examples, the number of access nodes for the child IAB node may be similarly calculated.

For example, referring to fig. 5, when the load status indicator of the IAB node 3 indicates a low load and the first threshold H1 is "50", the number of access nodes of the IAB node 3 is 50/2=25. When the IAB node 1 serves 100 UEs, i.e., the number of UEs directly connected to the IAB node is 100, the number of access nodes of the IAB node 1 may be calculated by: 100+25=125. The number of access nodes for IAB node 2 may be similarly calculated.

In other embodiments, the at least one threshold includes a first threshold (e.g., H1), a second threshold (e.g., H2), a third threshold (e.g., H3), and a fourth threshold (e.g., H4).

In these embodiments, the load status indicator indicates a low load of the IAB node if the number X of access nodes of the IAB node is less than a first threshold H1 and the number Y of IAB nodes of the IAB node is less than a third threshold H3. In case the number X of access nodes of the IAB node is equal to or greater than the second threshold H2 and the number Y of IAB nodes of the IAB node is equal to or greater than the fourth threshold H4, the load status indicator indicates a high load of the IAB node. Otherwise, the load status indicator indicates a medium load of the IAB node.

In some embodiments, the number of access nodes X of the IAB node is X1, as described above, and the number of IAB nodes Y of the IAB node is Y1, as described above. In other embodiments, the number of access nodes X of an IAB node is calculated based on the number of access nodes directly connected to the IAB node and the number of access nodes directly connected to respective downstream IAB nodes of the IAB node, and the number of IAB nodes Y of the IAB node is calculated based on the number of downstream IAB nodes Y2 of the IAB node. In one embodiment, the number of access nodes X of the IAB node may be X2, as described above, and the number of IAB nodes Y of the IAB node is Y2, as described above.

For example, referring to fig. 5, the number of access nodes for IAB node 1 may be calculated by equally dividing the number of access nodes for IAB node 3 between IAB node 1 and IAB node 2 and adding the divided number to the number of access nodes directly connected to IAB node 1. For example, when IAB node 1 is serving 100 UEs and its downstream IAB nodes (i.e., IAB node 3 and IAB node 4) are serving 50 UEs, i.e., the number of UEs directly connected to IAB node 1 is 100 and the number of UEs of IAB node 3 is 50, the number of access nodes of IAB node 1 may be calculated by: 100+50/2=125. The number of access nodes for IAB node 2 may be similarly calculated.

In this embodiment, the number of downstream IAB nodes of the IAB node may be similarly calculated as described above with respect to the number X of access nodes of the IAB node. For example, referring to fig. 5, when the number of child IAB nodes of IAB node 1 is 3 (i.e., IAB node 3 and IAB nodes 31 and 32 (not shown)), the number of downstream IAB nodes of IAB node 3 is M, IAB node 31 and the number of downstream IAB nodes of IAB node 32 is N and the number of parent IAB nodes of IAB node 31 and IAB node 32 is 1, respectively, the number of downstream IAB nodes of IAB node 1 may be calculated by: k+p/2+M/2+n+n, where k+p=the number of sub-IAB nodes of IAB node 1, P refers to the sub-node shared between IAB node 1 and IAB node 2, i.e., IAB node 3, and K refers to the remaining sub-IAB nodes of IAB nodes, i.e., IAB node 31 and IAB node 32. In the above example, k=2 and p=1. When the number of downstream IAB nodes of IAB node 3 is 2 (i.e., IAB node 4 and IAB node 5 (not shown)) and the number of downstream IAB nodes of IAB node 31 and IAB node 32 is 1, respectively, i.e., m=2 and n=1, the number of downstream IAB nodes of IAB node 1 may be calculated by: 2+1/2+2/2+1+1=5.5. The number of downstream IAB nodes of IAB node 2 may be similarly calculated. Alternatively, the number of IAB nodes Y of the IAB node may be the number of downstream IAB nodes Y2 of the IAB node.

In this embodiment, the number of downstream IAB nodes of the IAB node may be similarly calculated as described above with respect to the number X of access nodes of the IAB node. For example, referring to fig. 5, when the number of sub-IAB nodes (i.e., IAB node 3) of IAB node 1 is 1, the load status indicator of IAB node 3 indicates a low load, and the third threshold H3 is "2", the number of downstream IAB nodes of IAB node 3 is 2/2=1, and the number of access nodes of IAB node 1 may be calculated by: 1+2/2=2. Alternatively, the number of IAB nodes Y of the IAB node may be the number of downstream IAB nodes Y2 of the IAB node.

In some embodiments, the information for configuring the trigger condition may include a step size. The step size is equal to or greater than 1. In these embodiments, the trigger condition may be that the number of access nodes of the IAB node varies by equal to or greater than a step size. The number of access nodes for the IAB node may be determined as described above.

For example, the step size may be 1. In this example, the IAB node may report load information of at least one IAB node when the number of access nodes of the IAB node changes. In another example, the step size may be greater than 1. In this example, the IAB node may report load information for at least one IAB node when the number of access nodes of the IAB node varies by equal to or greater than a step size.

In other embodiments, the trigger information includes an indication of a change in the load status indicator. In these embodiments, the trigger condition may be a change in the load status indicator. The load status indicator of the IAB node may be determined as described above. For example, referring to fig. 6, when the load status indicator of the IAB node 3 changes from indicating a low load to indicating a medium load, for example, the IAB node 3 may report load information of at least one IAB node.

In some embodiments, the IAB node may broadcast the load information of the IAB node. In one embodiment, the load information of the IAB node comprises a load status indicator of the IAB node. For example, referring to fig. 6, the iab node 3 may broadcast its load information. The load information of the IAB node 3 may comprise a load status indicator of the IAB node 3.

In some embodiments, the IAB node may further broadcast load information of an upstream IAB node of the IAB node. In one embodiment, the load information of the upstream IAB node comprises a corresponding load status indicator of the upstream IAB node.

In some embodiments, the respective load status indicators of upstream IAB nodes of the IAB node are broadcast by parent IAB nodes of the IAB node.

For example, referring to fig. 6, the IAB node 3 may further broadcast load information of its upstream IAB node (e.g., IAB node 2). The load information of the IAB node 2 may comprise a load status indicator of the IAB node 2. The load information of the upstream IAB node of the IAB node 3 is broadcasted by the parent IAB node of the IAB node 3, i.e. the IAB node 2.

In some embodiments, the process in fig. 7 described above may occur during a handover process. In one embodiment, the BS may select a node from the candidate IAB nodes as a target IAB node to be handed over, and may transmit a handover command to the IAB node. The selection may be based on load information of the candidate IAB nodes. The selection may be further based on measurement results and/or other assistance information such as hop counts. After receiving the handover command, the IAB node may switch from the serving IAB node to the target IAB node.

For example, referring to fig. 6, the IAB donor may select a node (e.g., IAB node 1) as the target IAB node and transmit a command to handover IAB node 3 from IAB node 2 to IAB node 1.

In other embodiments, the process in fig. 7 described above may occur during the reconstruction process. For example, referring to fig. 6, rlf may occur on the backhaul link between IAB node 3 and IAB node 2. The IAB node 3 may initiate a reestablishment procedure, select candidate IAB nodes to reestablish the backhaul link, and access to the selected IAB node (e.g., IAB node 1). The selection may be based on load information of the candidate IAB nodes. The selection may be further based on measurement results and/or other assistance information such as hop counts.

For example, referring to fig. 6, the IAB node 3 may select a candidate node (e.g., IAB node 1) to reestablish the backhaul link and switch from the IAB node 2 to the selected candidate IAB node (e.g., IAB node 1).

Fig. 8 illustrates an exemplary process 800 for selecting a target node according to an embodiment of the invention.

In step 802, the bs may transmit information for configuring a trigger condition. Once the trigger condition is met, the IAB node may be triggered to report load information of at least one IAB node. In some embodiments of the present invention, the BS may be the IAB donor shown in fig. 3.

The bs may receive load information of at least one IAB node in step 804. In some embodiments of the invention, the load information comprises a load status indicator of the IAB node. Load information, such as a load status indicator, may be determined according to the exemplary process described above with respect to fig. 7.

In some embodiments of the invention, the trigger information comprises a step size. The step size is equal to or greater than 1. In other embodiments of the invention, the trigger information comprises an indication of a change in the load status indicator. The IAB node may determine when the trigger condition is met according to the exemplary process described above with respect to fig. 7.

In some embodiments of the invention, the load status indicator of the IAB node may indicate a load level of a plurality of load levels of the IAB node. In one embodiment, the load status indicator indicates a low load, a medium load, or a high load of the IAB node.

In some embodiments of the present invention, the BS may further transmit at least one threshold of the load status. In some embodiments, the load information, e.g., the load status indicator, is based on at least one threshold.

In some embodiments of the present invention, the BS may transmit a handover command to one of the at least one IAB node further based on the received load information. The handover procedure may be performed according to the exemplary procedure described above with respect to fig. 7.

Fig. 9 illustrates a block diagram of an apparatus 900 according to an embodiment of the invention.

As shown in fig. 9, an apparatus 900 may include a non-transitory computer-readable medium (not shown), receive circuitry 902, transmit circuitry 904, and a processor 906 coupled to the non-transitory computer-readable medium, the receive circuitry, and the transmit circuitry. The apparatus 900 may be a BS or an IAB node. Although elements such as processor, transmit circuitry, and receive circuitry are described in the singular in this figure, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments, the receive circuitry 902 and the transmit circuitry 904 are combined into a single device, such as a transceiver. In a particular embodiment, the apparatus 900 may further include an input device, a memory, and/or other components.

In some embodiments, a non-transitory computer-readable medium may have stored thereon computer-executable instructions that cause a processor to implement the methods described above with respect to an IAB node. For example, computer-executable instructions, when executed, cause the processor 906 to interact with the receive circuitry 902 and the transmit circuitry 904 in order to perform the steps depicted in fig. 7 with respect to an IAB node.

In other embodiments, a non-transitory computer-readable medium may have stored thereon computer-executable instructions that cause a processor to implement the methods described above with respect to a base station. For example, computer-executable instructions, when executed, cause the processor 906 to interact with receive circuitry 902 and transmit circuitry 904 in order to perform the steps depicted in fig. 8 with respect to a BS.

Those of ordinary skill in the art will appreciate that the steps of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the steps of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

While the invention has been described with reference to specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Moreover, all elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be able to make and use the teachings of the present invention by simply employing the elements of the independent claims. Accordingly, the embodiments of the invention set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.

In this document, the term "comprises/comprising" or any other variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element that starts with "a/an" or the like (without more constraint) does not exclude the presence of additional identical elements in a process, method, article or apparatus that comprises an element. Also, the term "another" is defined as at least a second or more. As used herein, the term "having" and the like are defined as "comprising.

Claims

1. A method for communication, comprising:

receiving information of a triggering condition for configuring a first integrated access and backhaul node to report load information of at least one integrated access and backhaul node; and

Reporting the load information of the at least one integrated access and backhaul node if the trigger condition is met, wherein the load information includes a load status indicator of the first integrated access and backhaul node.

2. The method of claim 1, wherein the at least one integrated access and backhaul node comprises the first integrated access and backhaul node.

3. The method of claim 1, wherein the at least one integrated access and backhaul node comprises a candidate parent integrated access and backhaul node for the first integrated access and backhaul node and an upstream integrated access and backhaul node for the candidate parent integrated access and backhaul node.

4. The method according to claim 1, wherein:

the information for configuring the trigger condition includes a step size, the step size being equal to or greater than 1; and is also provided with

The trigger condition is that a change in the number of access nodes of the first integrated access and backhaul node is equal to or greater than the step size.

5. The method according to claim 1, wherein:

the information for configuring the trigger condition includes an indication of a change in the load status indicator; and is also provided with

The trigger condition is the change in the load status indicator.

6. The method as recited in claim 1, further comprising: at least one threshold value of a load state is received.

7. The method as recited in claim 1, further comprising: a broadcast message containing at least one threshold of load status is received.

8. The method of claim 6 or 7, wherein the at least one threshold includes a first threshold and a second threshold, and wherein:

The load status indicator indicates a low load of the first integrated access and backhaul node if the number of access nodes of the first integrated access and backhaul node is less than the first threshold;

the load status indicator indicates a medium load of the first integrated access and backhaul node if the number of access nodes of the first integrated access and backhaul node is equal to or greater than the first threshold and less than the second threshold; and is also provided with

The load status indicator indicates a high load of the first integrated access and backhaul node if the number of access nodes of the first integrated access and backhaul node is equal to or greater than the second threshold.

9. The method of claim 8, wherein the number of access nodes is the number of access nodes directly connected to the first integrated access and backhaul node.

10. The method of claim 8, wherein the number of access nodes is calculated based on the number of access nodes directly connected to the first integrated access and backhaul node and the number of access nodes directly connected to respective downstream integrated access and backhaul nodes of the first integrated access and backhaul node.

11. The method of claim 10, wherein the first integrated access and backhaul node and at least one neighboring integrated access and backhaul node share sub-integrated access and backhaul nodes, the number of access nodes calculated by:

equally dividing the number of access nodes of the subset into access and backhaul nodes between the first integrated access and backhaul node and the at least one neighboring integrated access and backhaul node, and

the divided number of access nodes is added to the number of access nodes directly connected to the first integrated access and backhaul node.

12. The method of claim 10, wherein the number of access nodes is calculated by summing the number of access nodes directly connected to the first integrated access and backhaul node with the number of access nodes of a subset of the first integrated access and backhaul nodes into access and backhaul nodes, and wherein:

in the event that the load status indicator of the subset of access and backhaul nodes indicates low load, the number of access nodes of the subset of access and backhaul nodes is half of the first threshold;

In the case where the load status indicator of the subset of access and backhaul nodes indicates medium load, the number of access nodes of the subset of access and backhaul nodes is an average of the first threshold and the second threshold; and is also provided with

In the case where the load status indicator of the subset of access and backhaul nodes indicates a high load, the number of access nodes of the subset of access and backhaul nodes is half of the second threshold.

13. The method of claim 6 or 7, wherein the at least one threshold includes a first threshold, a second threshold, a third threshold, and a fourth threshold; and wherein:

the load status indicator indicates a low load of the first integrated access and backhaul node if a number of access nodes of the first integrated access and backhaul node is less than the first threshold and the number of integrated access and backhaul nodes of the first integrated access and backhaul node is less than the third threshold;

the load status indicator indicates a high load of the first integrated access and backhaul node if the number of access nodes of the first integrated access and backhaul node is equal to or greater than the second threshold and the number of integrated access and backhaul nodes of the first integrated access and backhaul node is equal to or greater than the fourth threshold;

Otherwise, the load status indicator indicates a medium load of the first integrated access and backhaul node.

14. The method according to claim 13, wherein:

the number of access nodes is the number of access nodes directly connected to the first integrated access and backhaul node, and

the number of integrated access and backhaul nodes is the number of access and backhaul nodes directly connected to a subset of the first integrated access and backhaul nodes.

15. The method according to claim 13, wherein:

the number of access nodes is calculated based on the number of access nodes directly connected to the first integrated access and backhaul node and the number of access nodes directly connected to respective downstream integrated access and backhaul nodes of the first integrated access and backhaul node, and

the number of integrated access and backhaul nodes is calculated based on the number of integrated access and backhaul nodes downstream of the first integrated access and backhaul node.

16. The method of claim 15, wherein the first integrated access and backhaul node and at least one neighboring integrated access and backhaul node share sub-integrated access and backhaul nodes, the number of access nodes calculated by:

17. The method of claim 15, wherein the number of access nodes is calculated by summing the number of access nodes directly connected to the first integrated access and backhaul node with the number of access nodes of a subset of the first integrated access and backhaul nodes into access and backhaul nodes, and wherein:

18. The method as recited in claim 1, further comprising:

load information of the first integrated access and backhaul node is broadcast, wherein the load information of the first integrated access and backhaul node includes the load status indicator of the first integrated access and backhaul node.

19. The method of claim 18, wherein the broadcasting load information of the first integrated access and backhaul node further comprises:

and broadcasting load information of an upstream integrated access and backhaul node of the first integrated access and backhaul node, wherein the load information of the upstream integrated access and backhaul node includes a corresponding load status indicator of the upstream integrated access and backhaul node.

20. The method of claim 19, wherein the respective load status indicators are broadcast by a parent integrated access and backhaul node of the first integrated access and backhaul node.

21. A method for communication, comprising:

Transmitting information for configuring a first integrated access and backhaul node to report a trigger condition for load information of at least one integrated access and backhaul node; and

The method includes receiving the load information of the at least one integrated access and backhaul node, wherein the load information includes a load status indicator of the first integrated access and backhaul node.

22. The method according to claim 21, wherein:

the information for configuring the trigger condition comprises a step size, the step size being equal to or greater than 1.

23. The method according to claim 21, wherein:

the information for configuring the trigger condition includes an indication of a change in the load status indicator.

24. The method of claim 21, wherein the load status indicator indicates at least one of: low load, medium load, and high load.

25. The method as claimed in claim 21, comprising: at least one threshold value of the load state is transmitted.

26. The method of claim 25, wherein the load status indicator is based on the at least one threshold.

27. The method as recited in claim 21, further comprising:

a handover command is transmitted to one of the at least one integrated access and backhaul nodes based on the received load information.

28. A non-transitory computer readable medium having stored therein computer executable instructions that cause a processor to implement the method of any one of claims 1-20.

29. A non-transitory computer readable medium having stored therein computer executable instructions that cause a processor to implement the method of any one of claims 21-27.

30. An apparatus for communication, comprising:

receiving circuitry;

transmitting circuitry; and

A processor coupled to the receive circuitry and the transmit circuitry, wherein the processor is configured to:

receiving, via the receive circuitry, information for configuring a first integrated access and backhaul node to report trigger conditions for load information of at least one integrated access and backhaul node; and

The load information of the at least one integrated access and backhaul node is reported via the transmit circuitry if the trigger condition is met, wherein the load information includes a load status indicator of the first integrated access and backhaul node.

31. An apparatus for communication, comprising:

receiving circuitry;

Transmitting circuitry; and

transmitting, via the transmit circuitry, information for configuring a first integrated access and backhaul node to report a trigger condition for load information of at least one integrated access and backhaul node; and

The load information of the at least one integrated access and backhaul node is received via the receive circuitry, wherein the load information includes a load status indicator of the first integrated access and backhaul node.